Had a clog in my nozzle (0.4mm) the other day. Went looking for a thin enough, inexpensive wire to push through the nozzle to remove any gunk or clogs. Finally found the perfect item at hobby lobby. They are 0.35mm flexible beading needles. Seem pretty soft and you get a dozen 4 inch needles for ~$3. They are flexible, but don’t appear to be hard enough to damage the nozzle. I was able to use one to remove the gunk and clog, then cut the end off and still had enough for 2 more clogs (which of course we all know will never happen) with the same needle.
Here’s the link if anyone is interested.